Method and system for high volume transfer of dies to substrates

ABSTRACT

A method, system, and apparatus for transferring dies to respective substrates is described. Conventional techniques include vision-based systems that pick and place dies one at a time onto substrates. The present invention can transfer multiple dies simultaneously or consecutively. Dies are loaded in a channel of a die application device. The dies are moved through the channel using any of a variety of means, such as gravity, air, vibration, a brush, a spring, etc. The die application device dispenses the dies onto respective substrates. In an aspect, the die application device independently dispenses each of the dies. In another aspect, the die application device dispenses multiple dies at a time.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to the assembly of electronic devices. More particularly, the present invention relates to the transfer of dies from wafers to substrates, including substrates of radio frequency identification (RFID) tags.

2. Related Art

Pick and place techniques are often used to assemble electronic devices. Such techniques involve a manipulator, such as a robot arm, to remove integrated circuit (IC) dies from a wafer and place them into a die carrier. The dies are subsequently mounted onto a substrate with other electronic components, such as antennas, capacitors, resistors, and inductors to form an electronic device.

Pick and place techniques involve complex robotic components and control systems that handle only one die at a time. This has a drawback of limiting throughput volume. Furthermore, pick and place techniques have limited placement accuracy, and have a minimum die size requirement.

One type of electronic device that may be assembled using pick and place techniques is an RFID “tag.” An RFID tag may be affixed to an item whose presence is to be detected and/or monitored. The presence of an RFID tag, and therefore the presence of the item to which the tag is affixed, may be checked and monitored by devices known as “readers.”

As market demand increases for products such as RFID tags, and as die sizes shrink, high assembly throughput rates for very small die, and low production costs are crucial in providing commercially-viable products. Accordingly, what is needed is a method and apparatus for high volume assembly of electronic devices, such as RFID tags, that overcomes these limitations.

SUMMARY OF THE INVENTION

The present invention is directed to methods, systems, and apparatuses for transferring dies to respective substrates. A die application device includes a body and a die application element. The body has a channel that is configured to receive a plurality of dies. The die application element is configured to transfer dies of the plurality of dies to respective substrates. In an aspect, the die application device includes a guide coupled to the body. A combination of the guide and the body laterally surround at least a portion of the channel. In an aspect, the guide and the body are a unitary element.

The die application element is configured to move along a first axis. The channel is configured along a second axis. The first axis and the second axis are typically perpendicular to each other.

In a first example, the die application element is configured to transfer a single die at a time. In a second example, the die application element is configured to transfer multiple dies at a time.

The die application device includes any number of cavities and/or die application elements. In an aspect, the die application device includes a plurality of cavities, each of which is capable of receiving a plurality of dies. Each channel is associated with a respective die application element. Die application elements are actuated independently from each other or in synchronism.

In another aspect of the present invention, dies are loaded in a channel of the die application device. The dies are moved through the channel to align at least one die with a die pedestal of the die application element. The die application element dispenses the dies onto respective substrates. The dies may be bonded onto the respective substrates.

These and other advantages and features will become readily apparent in view of the following detailed description of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS/FIGURES

The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention.

FIG. 1 shows a block diagram of an exemplary RFID tag, according to an embodiment of the present invention.

FIGS. 2A and 2B show plan and side views of an exemplary die, respectively.

FIGS. 2C and 2D show portions of a substrate with a die attached thereto, according to example embodiments of the present invention.

FIG. 3 is a flowchart illustrating a tag assembly process, according to embodiments of the present invention.

FIGS. 4A and 4B are plan and side views of a wafer having multiple dies affixed to a support surface, respectively.

FIG. 5 is a view of a wafer having separated dies affixed to a support surface.

FIG. 6 shows a system diagram illustrating example options for transfer of dies from wafers to substrates, according to embodiments of the present invention.

FIG. 7A shows a cross-sectional side view of a die application device, according to an embodiment of the present invention.

FIG. 7B shows a front view of the die application device of FIG. 7A, according to an embodiment of the present invention.

FIGS. 8A and 8B show perspective views of an example die application device, according to embodiments of the present invention.

FIGS. 9A-9C show side views of an example die application device, according to embodiments of the present invention.

FIGS. 10A-10C show side views of an example die application device, according to embodiments of the present invention.

FIG. 11 illustrates a flowchart of a method of transferring dies to respective substrates in accordance with an embodiment of the present invention.

The present invention will now be described with reference to the accompanying drawings. In the drawings, like reference numbers generally indicate identical, functionally similar, and/or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit(s) in the reference number.

DETAILED DESCRIPTION OF THE INVENTION

This specification discloses one or more embodiments that incorporate the features of this invention. The embodiment(s) described, and references in the specification to “one embodiment”, “an embodiment”, “an example embodiment”, etc., indicate that the embodiment(s) described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to effect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

1.0 Overview

The present invention provides improved processes and systems for assembling electronic devices, including RFID tags. The present invention provides improvements over current processes. Conventional techniques include vision-based systems that pick and place dies one at a time onto substrates. The present invention can transfer multiple dies simultaneously or consecutively. Vision-based systems are limited as far as the size of dies that may be handled, such as being limited to dies larger than 600 microns square. The present invention is applicable to dies 100 microns square and even smaller. Furthermore, yield is poor in conventional systems, where two or more dies may be accidentally picked up at a time, causing losses of additional dies. The present invention allows for improved yield values.

The present invention provides an advantage of simplicity. Conventional die transfer tape mechanisms may be used by the present invention. Furthermore, much higher fabrication rates are possible. Furthermore, because the present invention allows for flip-chip die attachment techniques, wire bonds are not necessary. Elements of the embodiments described herein may be combined in any manner.

1.1 Example Electronic Device

The present invention is directed to techniques for producing electronic devices, such as RFID tags. For illustrative purposes, the description herein primarily relates to the production of RFID tags. However, the description is also adaptable to the production of further electronic device types, as would be understood by persons skilled in the relevant art(s) from the teachings herein.

FIG. 1 shows a block diagram of an exemplary RFID tag 100, according to an embodiment of the present invention. As shown in FIG. 1, RFID tag 100 includes a die 104 and related electronics 106 located on a tag substrate 116. Related electronics 106 includes an antenna 114 in the present example. Die 104 can be mounted onto antenna 114 of related electronics 106. As is further described elsewhere herein, die 104 may be mounted in either a pads up or pads down orientation.

RFID tag 100 may be located in an area having a large number, population, or pool of RFID tags present. RFID tag 100 receives interrogation signals transmitted by one or more tag readers. According to interrogation protocols, RFID tag 100 responds to these signals. Each response includes information that identifies the corresponding RFID tag 100 of the potential pool of RFID tags present. Upon reception of a response, the tag reader determines the identity of the responding tag, thereby ascertaining the existence of the tag within a coverage area defined by the tag reader.

RFID tag 100 may be used in various applications, such as inventory control, airport baggage monitoring, as well as security and surveillance applications. Thus, RFID tag 100 can be affixed to items such as airline baggage, retail inventory, warehouse inventory, automobiles, compact discs (CDs), digital video discs (DVDs), video tapes, and other objects. RFID tag 100 enables location monitoring and real time tracking of such items.

In the present embodiment, die 104 is an integrated circuit that performs RFID operations, such as communicating with one or more tag readers (not shown) according to various interrogation protocols. Exemplary interrogation protocols are described in U.S. Pat. No. 6,002,344 issued Dec. 14, 1999 to Bandy et al. entitled System and Method for Electronic Inventory, and U.S. patent application Ser. No. 10/072,885 filed Feb. 12, 2002 entitled Method, System, and Apparatus for Binary Traversal of a Tag Population. Die 104 includes a plurality of contact pads that each provide an electrical connection with related electronics 106.

Related electronics 106 are connected to die 104 through a plurality of contact pads of IC die 104. In embodiments, related electronics 106 provide one or more capabilities, including RF reception and transmission capabilities, sensor functionality, power reception and storage functionality, as well as additional capabilities. The components of related electronics 106 can be printed onto a tag substrate 116 with materials, such as conductive inks. Examples of conductive inks include silver conductors 5000, 5021, and 5025, produced by DuPont Electronic Materials of Research Triangle Park, N.C. Other materials or means suitable for printing related electronics 106 onto tag substrate 116 include polymeric dielectric composition 5018 and carbon-based PTC resistor paste 7282, which are also produced by DuPont Electronic Materials of Research Triangle Park, N.C. Other materials or means that may be used to deposit the component material onto the substrate would be apparent to persons skilled in the relevant art(s) from the teachings herein.

As shown in FIG. 1, tag substrate 116 has a first surface that accommodates die 104, related electronics 106, as well as further components of tag 100. Tag substrate 116 also has a second surface that is opposite the first surface. An adhesive material or backing can be included on the second surface. When present, the adhesive backing enables tag 100 to be attached to objects, such as books and consumer products. Tag substrate 116 is made from a material, such as polyester, paper, plastic, fabrics such as cloth, and/or other materials such as commercially available Tyvec®.

In some implementations of tags 100, tag substrate 116 can include an indentation, “cavity,” or “cell” (not shown in FIG. 1) that accommodates die 104. An example of such an implementation is included in a “pads up” orientation of die 104.

FIGS. 2A and 2B show plan and side views of an example die 104. Die 104 includes four contact pads 204 a-d that provide electrical connections between related electronics 106 and internal circuitry of die 104. Note that although four contact pads 204 a-d are shown, any number of contact pads may be used, depending on a particular application. Contact pads 204 are made of an electrically conductive material during fabrication of the die. Contact pads 204 can be further built up if required by the assembly process, by the deposition of additional and/or other materials, such as gold and solder flux. Such post processing, or “bumping,” will be known to persons skilled in the relevant art(s).

FIG. 2C shows a portion of a substrate 116 with die 104 attached thereto, according to an example embodiment of the present invention. As shown in FIG. 2C, contact pads 204 a-d of die 104 are coupled to respective contact areas 210 a-d of substrate 116. Contact areas 210 a-d provide electrical connections to related electronics 106. The arrangement of contact pads 204 a-d in a rectangular (e.g., square) shape allows for flexibility in attachment of die 104 to substrate 116, and good mechanical connection. This arrangement allows for a range of tolerance for imperfect placement of IC die 104 on substrate 116, while still achieving acceptable electrical coupling between contact pads 204 a-d and contact areas 210 a-d. For example, FIG. 2D shows an imperfect placement of IC die 104 on substrate 116. However, even though IC die 104 has been improperly placed, acceptable electrical coupling is achieved between contact pads 204 a-d and contact areas 210 a-d.

Note that although FIGS. 2A-2D show the layout of four contact pads 204 a-d collectively forming a rectangular shape, greater or lesser numbers of contact pads 204 may be used. Furthermore, contact pads 204 a-d may be laid out in other shapes in embodiments of the present invention.

1.2 Device Assembly

The present invention is directed to continuous-roll assembly techniques and other techniques for assembling tags, such as RFID tag 100. Such techniques involve a continuous web (or roll) of the material of the tag antenna substrate 116 that is capable of being separated into a plurality of tags. Alternatively, separate sheets of the material can be used as discrete substrate webs that can be separated into a plurality of tags. As described herein, the manufactured one or more tags can then be post processed for individual use. For illustrative purposes, the techniques described herein are made with reference to assembly of RFID tag 100. However, these techniques can be applied to other tag implementations and other suitable devices, as would be apparent to persons skilled in the relevant art(s) from the teachings herein.

The present invention advantageously eliminates the restriction of assembling electronic devices, such as RFID tags, one at a time, allowing multiple electronic devices to be assembled in parallel. The present invention provides a continuous-roll technique that is scalable and provides much higher throughput assembly rates than conventional pick and place techniques.

FIG. 3 shows a flowchart 300 with example steps relating to continuous-roll production of RFID tags 100, according to example embodiments of the present invention. FIG. 3 shows a flowchart illustrating a process 300 for assembling tags 100. Process 300 begins with a step 302. In step 302, a wafer 400 having a plurality of dies 104 is produced. FIG. 4A illustrates a plan view of an exemplary wafer 400. As illustrated in FIG. 4A, a plurality of dies 104 are arranged in a plurality of rows 402 a-n.

In a step 304, wafer 400 is optionally applied to a support structure or surface 404. Support surface 404 includes an adhesive material to provide adhesiveness. For example support surface 404 may be an adhesive tape that holds wafer 400 in place for subsequent processing. FIG. 4B shows an example view of wafer 400 in contact with an example support surface 404. In some embodiments, wafer 400 does not need to be attached to a support surface, and can be operated on directly.

In a step 306, the plurality of dies 104 on wafer 400 are separated. For example, step 306 may include scribing wafer 400 according to a process, such as laser etching. FIG. 5 shows a view of wafer 400 having example separated dies 104 that are in contact with support surface 404. FIG. 5 shows a plurality of scribe lines 502 a-l that indicate locations where dies 104 are separated. In an embodiment, wafer 400 is only scribed in one direction, so that separated strips (e.g., rows or columns) of dies are formed.

In a step 308, the plurality of dies 104 is transferred to a substrate. For example, dies 104 can be transferred from support surface 404 to tag substrates 116. Alternatively, dies 104 can be directly transferred from wafer 400 to substrates 116. In an embodiment, step 308 may allow for “pads down” transfer. Alternatively, step 308 may allow for “pads up” transfer. As used herein the terms “pads up” and “pads down” denote alternative implementations of tags 100. In particular, these terms designate the orientation of connection pads 204 in relation to tag substrate 116. In a “pads up” orientation for tag 100, die 104 is transferred to tag substrate 116 with pads 204 a-204 d facing away from tag substrate 116. In a “pads down” orientation for tag 100, die 104 is transferred to tag substrate 116 with pads 204 a-204 d facing toward (and in contact with) tag substrate 116. In an embodiment, as described below, dies are transferred using a die application device that holds the strips of dies formed in step 306.

Note that step 308 may include multiple die transfer iterations. For example, in step 308, dies 104 may be directly transferred from a wafer 400 to substrates 116. Alternatively, dies 104 may be transferred to an intermediate structure, and subsequently transferred to substrates 116.

Note that steps 306 and 308 can be performed simultaneously in some embodiments. This is indicated in FIG. 3 by step 320, which includes both of steps 306 and 308. In a step 310, post processing is performed. During step 310, assembly of RFID tag(s) 100 is completed.

2.0 Die Transfer Embodiments

Step 308 shown in FIG. 3, and discussed above, relates to transferring dies to a tag substrate. The dies can be attached to a support surface (e.g., as shown in FIG. 5), or can be transferred directly from the wafer, and can be transferred to the tag substrate by a variety of techniques. Conventionally, the transfer is accomplished using a pick and place tool. The pick and place tool uses a vacuum die collet controlled by a robotic mechanism that picks up the die from the support structure by a suction action, and holds the die securely in the die collet. The pick and place tool deposits the die into a die carrier or transfer surface. For example, a suitable transfer surface is a “punch tape” manufactured by Mulbauer, Germany. A disadvantage of the present pick and place approach is that only one die at a time may be transferred. Hence, the present pick and place approach does not scale well for very high throughput rates.

The present invention allows for the transfer of more than one die at a time from a support surface to a transfer surface. In fact, the present invention allows for the transfer of more than one die between any two surfaces, including transferring dies from a wafer or support surface to an intermediate surface, transferring dies between multiple intermediate surfaces, transferring dies between an intermediate surface and the final substrate surface, and transferring dies directly from a wafer or support surface to the final substrate surface.

FIG. 6 shows a high-level system diagram 600 that provides a representation of the different modes or paths of transfer of dies from wafers to substrates. FIG. 6 shows a wafer 400, a web of substrates 606, and a transfer surface 608. Two paths are shown in FIG. 6 for transferring dies, a first path 602, which is a direct path, and a second path 604, which is a path having intermediate steps. For example, as shown in FIG. 6, first path 602 leads directly from wafer 400 to web 606. In other words, dies can be transferred from wafer 400 to substrates of web 606 directly, without the dies having first to be transferred from wafer 400 to another surface or storage structure. However, according to path 604, at least two steps are required, path 604A and path 604B. For path 604A, dies are first transferred from wafer 400 to an intermediate transfer surface 608. The dies then are transferred from transfer surface 608 via path 604B to the substrates of web 606. Paths 602 and 604 each have their advantages. For example, path 602 can have fewer steps, but can have issues of die registration, and other difficulties. Path 604 typically has a larger number of steps than path 602, but transfer of dies from wafer 400 to a transfer surface 608 can make die transfer to the substrates of web 606 easier, as die registration may be easier.

According to embodiments of the present invention, a die application tool or device is used to transfer dies to surfaces, such as substrates, including substrates of a web.

FIG. 7A shows a cross-sectional side view of a die application device 700, according to an example embodiment of the present invention. FIG. 7B shows a front view of die application device 700, according to an embodiment of the present invention. Die application device 700 is used to transfer dies 104 to surfaces, such as substrates 116. As shown in FIGS. 7A and 7B, die application device 700 includes a body 710. Body 710 has length 702 shown in FIG. 7A, and a width 704 shown in FIG. 7B. Body 710 has a channel 706 formed in a top surface 708 along length 702. Channel 706 is a groove or slot in top surface 708 configured to hold a row or column of integrated circuit chips or dies during operation of die application device 700.

As shown in FIGS. 7A and 7B, body 710 further includes a guide chamber 712, which is open at a side surface 714 of body 710, and also at top surface 708, where top surface 708 intersects with side surface 714. Guide chamber 712 has a rectangular shape, and is configured to contain and guide a die application element 730 during operation of die application device 700. As shown in FIGS. 7A and 7B, die application element 730 resides in guide chamber 712, and is moveable along an axis 716.

Die application element 730 has a die pedestal 718. During operation of die application device 700, a die in channel 706 is moved from channel 706 onto die pedestal 718. The position of the die relative to die pedestal 718 is maintained by any of a variety of means, such as a vacuum. Die application element 730 is actuated in a first direction (shown as an upward direction in FIGS. 7A and 7B) along axis 716 through guide chamber 712 to move the die in the first direction. The die is thereby made accessible from die application device 700, and can be applied to a subsequent surface or otherwise utilized.

For instance, FIGS. 8A-8B show example operation of die application device 700. FIGS. 8A-8B show perspective views of die application device 700 during operation, according to embodiments of the present invention. As shown in FIG. 8A, a row of dies 104 are present in channel 706. Furthermore, dies 104 in channel 706 have been incremented such that a first die 104 a is positioned on die pedestal 718 of die application element 730. As shown in FIG. 8B, die application element 730 has been actuated, to move upward along axis 716. Die 104 a can be transferred from die pedestal 718 to a subsequent surface. In FIGS. 8A-8B, a cover plate 802 is coupled to top surface 708 for illustrative purposes. Cover plate 802 encloses channel 706, thereby securing dies 104 that are moved along channel 706 toward die pedestal 718.

3.0 Other Embodiments

Die application device 700 is capable of being operated in any orientation. For instance, FIGS. 9A-9C show perspective views of die application device 700 oriented to transfer dies 104 downward onto surfaces, such as substrates. In FIG. 9A, channel 706 is open at a bottom surface 908 of body 710. Die application device 700 includes a guide 902 coupled to bottom surface 908 of body 710 to provide structural support for dies 104 that are moved through channel 706 toward die pedestal 718.

Referring to FIG. 9A, the combination of guide 902 and body 710 laterally surrounds at least a portion of channel 706. The term “laterally surround” as used herein means to “define a perimeter of”. The laterally surrounded portion of channel 706 is referred to as being enclosed, though not all sides of channel 706 need to be surrounded or covered. For example, channel 706 may have a cylindrical shape with one or both ends being uncovered. In this example, the enclosed portion is the entire channel 706. According to an embodiment, body 710 and guide 902 are a unitary element.

Channel 706 may be configured to receive dies in any of a variety of arrangements. In a first aspect, channel 706 is configured to receive a linear array of dies. The linear array includes a single row or column of dies or multiple rows or columns of dies. In a second aspect, channel 706 is configured to receive a random or pseudo-random arrangement of dies. For instance, dies 104 may be moved to a corner or a relatively narrow portion of channel 706 to orient at least one of the dies 104 relative to die application element 730.

Channel 706 is provided between walls of body 710. In a first embodiment, the walls are substantially parallel. In a second embodiment, the distance between the walls decreases toward die application element 730. Channel 706 has a proximal end and a distal end with respect to die application element 730. In the second embodiment, the walls are closer to each other at the proximal end than at the distal end.

As shown in FIG. 9B, dies 104 are moved through channel 706 in a direction indicated by arrow 940. In FIG. 9B, dies 104 are moved substantially parallel with bottom surface 908 of body 710, though the scope of the present invention is not limited in this respect. Dies 104 are moved through channel 706 in any of a variety of ways. According to a first embodiment, air is used to push and/or a vacuum is used to pull dies 104 along guide 902. In a second embodiment, vibration is used to facilitate moving dies 104. According to a third embodiment, body 710 and guide 902 are not necessarily fixably attached to each other. In an aspect, guide 902 moves with reference to body 710 in the direction indicated by arrow 940 until guide 902 reaches a threshold or an obstacle. The obstacle may be coupled to body 710 along surface 908, for instance. In another aspect, dies 104 rest upon guide 902 as guide 902 moves along surface 908 of body 710. In a fourth embodiment, a lever, an arm, and/or a spring is used to move dies 104 in the direction indicated by arrow 940. The lever, arm, and/or spring is coupled to body 710 or guide 902. According to a fifth embodiment, a brush is used to move dies 104 through channel 706. The brush is moved in the direction indicated by arrow 940, such that the brush is placed in contact with one or more dies 104, thereby moving one or more dies 104 along guide 902.

Referring to FIG. 9B, die 104 a is aligned with die pedestal 718 for transfer to a respective substrate. In FIG. 9B, one die 104 a at a time is aligned with pedestal 718 for illustrative purposes. Any number of dies 104 may be aligned with pedestal 718 of die application element 730. As shown in FIG. 9C, die application element 730 is actuated in a direction indicated by arrow 950, thereby making die 104 a accessible from die application device 700. Die application element 730 is actuated by any of a variety of means, such as an electromechanical solenoid or a servo-controlled linear drive.

Upon transferring die 104 a to a substrate, die application element 730 moves in a direction opposite that indicated by arrow 950. Dies 104 that remain in channel 706 are incremented in a direction indicated by arrow 940 of FIG. 9B to align the next successive die with die pedestal 718 of die application element 730. Die application element 730 is again actuated in the direction indicated by arrow 950, such that the die that is aligned with die pedestal 718 is transferred to a respective substrate. This process can be repeated for any number of dies 104.In FIGS. 10A-10C, die application device 700 is configured to transfer more than one die 104 at a time from channel 706. For example, in FIG. 10A, die application device 730 is capable of transferring five dies 104 at a time FIG. 10B, dies 104 are moved in the direction indicated by arrow 940, so that dies 104 a-e are aligned with die pedestal 718 of die application element 730. Five dies 104 a-e are aligned with surface 735 for illustrative purposes. Any number of dies may be aligned with die pedestal 718. In FIG. 10C, die application element 730 is moved in the direction indicated by arrow 750, thereby transferring dies 104 a-e from channel 706.

FIG. 11 illustrates a flowchart 1100 of a method of transferring dies to respective substrates in accordance with an embodiment of the present invention. The invention, however, is not limited to the description provided by the flowchart 1100. Rather, it will be apparent to persons skilled in the relevant art(s) from the teachings provided herein that other functional flows are within the scope and spirit of the present invention.

Flowchart 1100 will be described with continued reference to example die application device 700 described above in reference to FIGS. 7A-10C, though the method is not limited to those embodiments.

Referring now to FIG. 11, a plurality of dies 104 is loaded in a channel 706 of a die application device 700 at block 1110. According to an embodiment, a wafer includes a plurality of rows, each row having a plurality of dies. A row of the wafer is loaded in channel 706 of die application device 700.

The plurality of dies 104 are moved through channel 706 to align at least one die of the plurality of dies 104 with a die pedestal 718 of die application device 700. The plurality of dies 104 may be moved by pushing or pulling the dies 104 using air, by vibrating the dies 104, or by any other means. In an aspect, the dies 104 are moved using a mechanical means, such as a spring, a brush, or a guide 902 that can move independently from a body 710 of die application device 700. For example, guide 902 carries the dies 104 toward die application element 730 for dispensing.

Die application device 700 dispenses the dies 104 onto respective substrates 116 at block 1120. In a first embodiment, die application device 700 independently dispenses each die of the plurality of dies 104. In a second embodiment, die application device 700 dispenses multiple dies at a time.

Die application device 700 includes any number of channels 706 and/or die application elements 730. According to an embodiment, die application device 700 includes a plurality of channels 706, each of which is capable of receiving a plurality of dies 104. Dies in each channel 706 are moved as described above with respect to FIGS. 7A-10C. Each channel 706 is associated with a respective die application element 730. A first die is aligned with a first surface of a first die application element, a second die is aligned with a second surface of a second die application element, and so on. The die application elements are actuated independently from each other or in synchronism.

4.0 Conclusion

While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example, and not limitation. It will be apparent to persons skilled in the relevant arts that various changes in form and detail can be made therein without departing from the spirit and scope of the invention. Thus the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents. 

1. A method of transferring dies to respective substrates, comprising: loading a plurality of dies in a channel of a die application device; and dispensing the dies onto respective substrates.
 2. The method of claim 1, further comprising: moving the plurality of dies through the channel to align at least one die of the plurality of dies with a surface of a die application element of the die application device.
 3. The method of claim 2, wherein moving the plurality of dies includes pushing the dies with air.
 4. The method of claim 2, wherein moving the plurality of dies is performed using a vacuum.
 5. The method of claim 2, wherein moving the plurality of dies includes vibrating the plurality of dies.
 6. The method of claim 2, wherein moving the plurality of dies includes carrying the plurality of dies on a guide of the die application device toward a die application element of the die application device.
 7. The method of claim 2, wherein moving the plurality of dies is performed using a spring.
 8. The method of claim 2, wherein moving the plurality of dies is performed using a brush.
 9. The method of claim 1, wherein dispensing the dies includes independently dispensing each die of the plurality of dies.
 10. The method of claim 1, wherein dispensing the dies includes actuating a die application element of the die application device using a servo-controlled linear drive.
 11. The method of claim 1, wherein dispensing the dies includes actuating a die application element of the die application device using an electromechanical solenoid.
 12. The method of claim 1, further comprising: tacking the dies onto the respective substrates using pressure.
 13. The method of claim 1, further comprising: bonding the dies onto the respective substrates using pressure and heat.
 14. An apparatus to transfer dies to respective substrates, comprising: a body having a channel that is configured to receive a plurality of dies; and a die application element that is configured to transfer dies of the plurality of dies to respective substrates.
 15. The apparatus of claim 14, further comprising a guide coupled to the body, wherein a combination of the guide and the body laterally surrounds at least a portion of the channel.
 16. The apparatus of claim 15, wherein the body and the guide are a unitary element.
 17. The apparatus of claim 14, wherein the die application element is provided in an opening of the body.
 18. The apparatus of claim 14, wherein the die application element is configured to move along an axis that is substantially perpendicular to an axis of the channel.
 19. The apparatus of claim 14, wherein the die application element is configured to move along a first axis and the channel is configured along a second axis, and wherein the first axis and the second axis are configured at an angle that enables gravity to facilitate movement of the plurality of dies toward die application element.
 20. The apparatus of claim 14, wherein the die application element is configured to transfer a single die at a time.
 21. The apparatus of claim 14, wherein the die application element is configured to transfer multiple dies at a time.
 22. The apparatus of claim 14, further comprising: a second die application element that is configured to transfer dies of a second plurality of dies to respective substrates, wherein the body further has a second channel that is configured to receive the second plurality of dies. 